1. Field of the Invention
The present invention relates to a sensor for detecting infrared rays.
2. Description of Related Art
An infrared sensor for detecting infrared rays contained in a package can is shown in JP-A-2003-270047. In this infrared sensor, an optical filter through which infrared rays pass is disposed at an opening of a package can, and a detector element that detects the infrared rays passing though the filter is contained in the package can. The infrared sensor of this type is large in size and heavy in weight because it is contained in the package can. A cap and a stem of the package can have to be connected to each other after the filter and the detector element are contained in the package can. This makes a manufacturing cost of the infrared sensor high. In addition, it has been strongly required to make the infrared sensor small in size, light in weight and inexpensive.